1. Field of the Invention
This invention relates to receipt of RF frequency broadcasts, and more particularly to a receiving system capable of receiving and processing analog audio broadcasts as well as digital audio broadcasts (DAB).
2. Description of the Related Art
Recently, digital audio broadcasting (DAB) systems have been developed capable of providing digital signals broadcast on existing AM (amplitude modulation) and FM (frequency modulation) spectrum allocations. The ability to broadcast on these radio frequencies uses In Band On Channel (IBOC) technology. In general, IBOC provides the ability to transmit a broadcast on a radio frequency (RF) carrier with conventional AM or FM modulation (e.g. analog modulation) as well as digital modulation centered on the same RF carrier. As such, an RF signal generated with IBOC consists of an analog portion and a digital portion of the modulation sharing the same RF carrier frequency.
Since IBOC signals are sent on standard RF carrier frequencies, the signals may be received by a conventional AM and/or FM radio receiver. However, conventional AM and/or FM radio receivers process only the analog portion of the IBOC signal. To achieve the increased sound quality available from the digital portion of the RF signal, the radio receiver must include additional processing capability.
Radio receivers capable of processing both the analog and the digital portions of the RF signal may perform the processing in the analog domain, the digital domain or some combination thereof. These receivers include circuitry exclusively for processing the analog portion and parallel circuitry exclusively for processing the digital portion. This redundant functionality for independently processing the analog portion and the digital portion may increase the complexity of the receiver. The increased complexity may result in increased manufacturing and hardware costs as well as requirements for a larger space to accommodate such a receiver.